Large arrangements of red and green varieties of Galactic leaf lettuce can be artistic and yummy. Leaf lettuce is easy to grow, and gardeners can harvest however much they want and whenever they want it.

Large arrangements of red and green varieties of Galactic leaf lettuce can be artistic and yummy. Leaf lettuce is easy to grow, and gardeners can harvest however much they want and whenever they want it.

Photo: Handout /MCT

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Bruce Frasier, president of Dixondale Farms, holds a bunch of vidalia onion transplants at the Carrizo Springs area farm on Thursday, December 27, 2007. Dixondale Farms grows 61 percent of the onion transplants in the nation and also grows cantalopes. According to Frasier, NAFTA has an adverse effect on his onion farming when the onion prices in Mexico get cheap. less

Bruce Frasier, president of Dixondale Farms, holds a bunch of vidalia onion transplants at the Carrizo Springs area farm on Thursday, December 27, 2007. Dixondale Farms grows 61 percent of the onion ... more

Photo: Wendi Poole, Freelance / For The Chronicle

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vegetable garden Fotolia

vegetable garden Fotolia

Photo: Fotolia / Anne Kitzman - Fotolia

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Get onion sets to transplant into the winter garden.
Young onions (Allium)

Get onion sets to transplant into the winter garden.
Young onions (Allium)

Photo: Getty Images / Getty Images

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Onions can easily be grown in bins or containers.

Onions can easily be grown in bins or containers.

Photo: Eric Kayne / For The Chronicle

Calvin Finch: Growing onions and lettuce in containers

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It is a great time of the year to grow flowers in containers and the garden, but have you thought about vegetables, specifically lettuce and onions? Both are easy to grow, productive and attractive.

I like a half whiskey barrel but any container larger than about 12 inches in diameter will make a nice display and produce vegetables for the table.

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Leaf lettuce transplants are available in three or four different colors at area nurseries. Use a row of the mixed colors in a border around the edge of the container and then plant the onions in the middle.

The larger the container, the more onion plants that can be planted in the center of the container.

A half whiskey barrel with eight lettuce plants around the edge could probably handle about 30 onions spread over the middle of the container. The 12-inch container may support two lettuce plants and eight onions.

Lettuce can be planted by seed if you can wait for the plants to mature. Remember the seed must not be covered with soil. It only germinates if it is on the soil surface.

Onion transplants are available in bundles at area nurseries. One bundle may include about 90 plants, enough for two 8-foot rows if they are planted 2 inches apart. It works well to share the plants in the bundle with neighbors or to plant one row in the garden and then plant the rest in containers.

Fill your container with a high-quality potting mix. In addition to the potting mix, all containers will require drainage holes so that water does not puddle in the pot.

Both lettuce and onions require heavy fertilization to provide a good yield. Prepare the soil in the garden with 4 cups of slow-release or winterizer lawn fertilizer per 100 square feet of bed. In the container use Osmocote or a similar slow-release product especially for containers for the initial nutrient application.

To maintain the required high level of nutrients, the onions in the garden can be sidedressed with more of the lawn fertilizer every three weeks. In the container, you have the option of adding more Osmocote every three weeks, or you can fertilize every week when you water with a soluble fertilizer such as Miracle-Gro or Peters.

The onions eventually will produce bulbs 3 to 4 inches across if they have the room, so not only is it desirable to harvest green onions as the season progresses, it is necessary if you want the final onions to reach full size.

The lettuce can be harvested leaf by leaf as you need it for salads and garnishes, or you can harvest the whole top two or three times during the season.

When I harvest lettuce (or spinach and other greens) leaf by leaf, I always leave more than half of the foliage in place. Treated in this manner, a highly fertilized lettuce plant will remain productive and attractive through May.

If you have children or grandchildren, it is great fun to build on the idea of container gardening. Each young person could have his or her own container and make some independent decisions about what to plant. In addition to the four types of leaf lettuce, there are three colors of high-quality short-day onions available at most nurseries.

The young gardeners could even include carrots, beets or bright lights chard in a container planting. All are easy to grow and attractive.